1. Technical Field
The present disclosure relates to orthopedic screw systems for bone fixation, and more particularly, to providing facet joint fixation screw systems with anti-backout features which prevent unintentional withdrawal of the screw.
2. The Relevant Technology
Loosening is a commonly encountered problem with screw fixation. A screw may work its way loose over time, such that fixation is compromised or the screw head protrudes to an undesirable extent from the surrounding material. Loosening is seen in orthopedic applications, such as facet joint fixation or facet joint fusion, at least partially because normal physiologic movement tends to encourage screw migration, and the bone into which the screw is driven tends to remodel over time. The three-dimensional topography of the bone surface presents an additional challenge in achieving secure fixation. The present disclosure provides a low-profile, self-contained, polyaxial, one-way screw and washer system that automatically and continuously resists any tendency of the screw to unthread from the surrounding material.